Even though exploration for natural gas through hydraulic fracturing requires significant water consumption in Texas, the new consumption is offset by the overall water efficiencies of shifting electricity generation from coal to natural gas, the study says.

The researchers estimate that water saved by shifting a power plant from coal to natural gas is 25 to 50 times as great as the amount of water used in fracking to extract the natural gas. Natural gas also enhances drought resilience by providing so-called peaking plants to complement increasing wind generation, which doesn’t consume water.

The researchers estimate that in 2011 alone, Texas would have consumed an additional 32 billion gallons of water — enough to supply 870,000 average residents — if all its natural gas-fired power plants were instead coal-fired plants, even after factoring in the additional consumption of water for hydraulic fracturing to extract the natural gas.

Fracking in drought-stricken South Texas used more than 14 billion gallons of water last year, the San Antonio Express-News reports. The number is far greater than estimates of what the Eagle Ford Shale oil field might use in the next decade.

An earlier study from the University of Texas at Austin, funded by the oil and gas industry, had predicted that fracking in the Eagle Ford would use a maximum of around 35,000 acre-feet of water annually.